The Justice Department yesterday asserted its power to investigate alleged misconduct by independent counsel Kenneth W. Starr, while President Clinton's former business partner, Susan McDougal, vowed an "all-out fight" against the alleged excesses of Starr's office as her latest trial began.

Less than a month after the Senate acquitted Clinton on perjury and obstruction-of-justice charges referred by Starr, the independent counsel finds himself the focus of attack on multiple fronts.

The Justice Department has advised Starr of its intent to investigate his handling of the Monica S. Lewinsky matter, and in papers filed yesterday with the special court that oversees independent counsels the department argued that the court has no power to block the disciplinary inquiry.

In his own filing, Starr urged the court not to heed a conservative legal group seeking an order to block Justice from investigating him. But Starr left open the possibility of mounting his own challenge if the Justice Department decides to proceed with an ethics investigation of his conduct.

Justice is weighing allegations that Starr's prosecutors misled top officials when they sought approval to investigate the Lewinsky matter and violated Justice's own guidelines when they confronted Lewinsky without her lawyer last year.

McDougal is seeking to raise similar claims of prosecutorial misconduct in her trial in Little Rock, where jury selection began yesterday. As she entered the courthouse, McDougal accused Starr's prosecutors of engaging in a "personal vendetta" to force her to testify against President Clinton, her former partner in the ill-fated Whitewater real estate investment.

McDougal has already served 18 months for civil contempt for refusing to answer questions about Clinton's involvement and now is being tried on criminal contempt and obstruction-of-justice charges that carry the possibility of 10 years in prison.

The threat of turning tables on Starr became much more serious last Friday when U.S. District Judge George Howard Jr. ruled that he would consider allowing Geragos to present evidence of "prosecutorial misconduct or outrageous government conduct."

McDougal claims that the independent counsel threatens and punishes witnesses who refuse to help him attack Clinton. Saying that this pattern was evident in his handling of Lewinsky, who escaped Starr's wrath only by agreeing to testify for him, Geragos has suggested he might subpoena Lewinsky to testify in the Little Rock trial.

The only figure indicted by Starr in the Lewinsky probe, Julie Hiatt Steele, is mounting a similar attack on his tactics. Steele is accused of lying to the grand jury about whether her former friend, Kathleen E. Willey, told her of an alleged sexual advance by Clinton. Steele's lawyer, Nancy Luque, has argued for dismissal of the indictment, saying in court papers that "it is irreversibly tainted by the ethical violations of the Office of Independent Counsel constituting prosecutorial misconduct."

Luque said yesterday that Steele's experience illustrates "why Susan McDougal is afraid to testify for Mr. Starr. Julie told him the truth and look what happened to her. He doesn't want the truth. He wants only to punish those who won't go along with his agenda."

Starr's prosecutors have brushed aside the allegations. "We know in any high-profile case, it is a normal thing where the prosecutor is attacked," Ewing said.

Both Starr and the Justice Department responded yesterday to a petition by the Landmark Legal Foundation, a conservative advocacy group, asking the judges to prohibit the department from investigating any independent counsel.

Reacting to the news that Attorney General Janet Reno had notified Starr of her intent to investigate him for potential misconduct in his handling of Lewinsky, the foundation argued that any such inquiry would infringe on the independence that is the very reason for appointing an outsider like Starr to examine allegations raised against a president.

In his court filings Starr asked the judges to dispose of the matter simply by finding that the foundation lacks the legal standing to enter into the matter, and he made a point of asking the judges not to consider the larger question of whether Reno has the authority to investigate him. If the judges decide to address that question, Starr asked for the opportunity to come back with a fuller statement of his views.

The Justice Department also asked the judges to reject the foundation's request but offered a full-fledged defense of its institutional prerogatives. The department claimed that the law creating the independent counsel process and a 1988 Supreme Court decision upholding it gives the judges well-defined but limited roles that do not include interfering with an attorney general investigating possible misconduct.

The authority to conduct such an inquiry is "inherent," Reno argued, in a provision of the law that gives an attorney general the power to remove an independent counsel for "good cause."

Mark R. Levin, president of the Herndon-based foundation, said in a statement that judges themselves must now decide how their responsibilities are to be met, reiterating the claim that by threatening Starr with an investigation, Reno is "attempting to improperly influence and interfere with the independent counsel's investigation."